Solid-hase hemadsorption: a method for rapid detection of Treponema pallidum-specific IgM.

A solid-phase hemadsorption (SPHA) technique for the rapid detection of Treponema pallidum-specific IgM antibodies is described. The demonstration of these immunoglobulins permits differentiation between a recent and a long-lasting infection and facilitates the decision as to whether or not a patient should receive therapy for syphilis. Errors that occur in the fluorescent treponemal antibody-absorbed test with IgM conjugate (IgM-FTA-Abs test) because of high titers of T. pallidum-specific IgG (competitive inhibition), rheumatoid factors, or 7S IgM do not occur with the SPHA technique. This test is easy to perform; it requires only microtiter plates coated with antisera to human IgM in addition to the standard T. pallidum hemagglutination reagents. As compared with the Veneral Disease Research Laboratory (vdrl) test, SPHA test has the advantage of being specific for T. pallidum; furthermore, IgM antibodies can be demonstrated earlier after infection and disappear sooner after adequate treatment of syphilis.